Crumbled vanilla wafers or Lotus cookies, for garnish
Generous pinch fine sea salt
Maraschino cherries, for topping (optional)
Place two 9x5-inch loaf pans into the freezer to chill. Combine the condensed milk, cinnamon, vanilla, and salt in a large bowl until incorporated. If you have time, chill in the fridge for 30–45 minutes.
In a separate bowl, whip the cream—you can use a stand mixer fitted with the whisk attachment, an electric hand mixer, or a plain ol’ whisk—until firm peaks form, 2 minutes. Divide the whipped cream equally into two bowls.
Remove the condensed milk mixture from the fridge and divide in half into two bowls. In one bowl, whisk in ¼ cup cocoa powder. Gently fold ½ cup of the whipped cream into each bowl of condensed milk mixture, then fold in the rest of the divided whipped cream into each bowl until everything is incorporated. But make sure not to overfold, because air is your friend here, and the more you fold the more you deflate the ice cream!
Transfer the mixture to two chilled loaf pans. Cover with plastic wrap, and chill for 2 hours.
Remove from the freezer, uncover, and gently stir in the chopped chocolate or mini chips into both ice creams. Cover and return to the freezer until firm, another 2–3 hours.
Scoop, divide among bowls, and top with crumbled cookies and maraschino cherries.